Ignition timing control



Sept. 27, 1938. E. V l-l. -sHEPARD IGNITION TIMI'NG CONTROL Filed Feb. 28, V1956 v 2,se{s-sneet1v v vANcs la N f ENG/Ngs SIDE CPBUEE TOE Sl DE* SPARK ADVANCE sept.27, 1938. EHSHEPAR'Df l y -2,1231,413k

IGNITIoNfTIMING CONTROL D10/1D VACUUM 4T NOT OPERATINGL y VACUUM Z /NcHL-s HG D/.STR/BUTQR WITH curoFF o/:EPAT/NG.

NQOo

ENG/NE lap/v1. l 30ol 600| 4.00 fk |3200. v490g CARM/1.55pm: Hoc/.Q rc)v 20 .30 40 .50 00 70 y8O figw/ `TN 0 U T CUT- OFF DEGREES INV'ENTOR 0 ENG/NE 2RM. I @oq l* I can 1v1/.Es PER Hou/a 1o zo so 40 o eo 7o a@ U .Ix i QRNEYSQ- JEH www sure zone within-y theengine'intake pip'e,in its over the centrifugal timing curve, during the engine idling speeds, and during the extremely high engine speeds. From the same standpoints it is also desirable to have a gradually effected shift in spark timing at each end of a rangefef predetermined'shift, so that the auxiliary control may be blended in with the centrifugal control. Ignition timing by centrifugal means, Ythat opf erate more or strictly in accordance with engine speeds, havefbeen well developed for some time. With the addition of the herein pro-I posed engine operated control means, it is prii `iectly practical to fabricate control mechanism that may be superimposed upon thespeed" responsive or centrifugalv control mechanism, rand thereby accomplish each and-all of -theobjectivea herein set out.

In accomplishing the objects oi.' ,thisiriyelitiorlml provisions have been incorporated in the carbure` tor part adjacent the point to which the suction minis connected? for critically Proportionie'g.; .the effect ofthe high pressurezone and theglow presactuation inthev diaphragm rof.` the suction unit.

f `opensonthecarburetoriside of thethrottle valve,

the throttle valve, the Athrottle valve dividingor separating the induction pipe into what be .alled a high PICSSUT@ 5120116 a. 19V-191755511113 Azone, respectively. -s The, have ,an outside connection by means of an intrruptible-j-passage,

and are eventually infcomrnunication r'v vitliZthe l ixus-.ehn extensionf the ihottl sha1? Das-.ies through this ponnectinanasseae ,and carries vente Lor cross bores-therethrough@andi-located, angu- I i i .thatrotation of the. throttle shaft 'effects the in- 'larly with respecttothe connectingpassage such terruptible connection. By the 1 saine -movement site pressureuzones. i 45 trede wille.. tirnerfdistributor cups appropriately` .hooked`V up the - r more detailed ...tov an'expansion ychamber .or' motive un`t`140 having .bymeans of screwsas 'illustratedgin Fig.A 5. The circuit breakermechanism includes a pair V-of block 28. in Y@operable.relation witha camk 28 `e0 ,by nyweigme '2 `earned byjawei'ght bite 34" mounted on anV engine driven shaft 88. .The speed Yresponsive `mechanism is the Y subjectmatter of prior art patents, andfis .not here claimed'fbut operates to y'control the ignition timing, in. ac-

,. .cordance withenginef speed, substantially as Ain- -dicated by thel dashed-linecurve appearingin -.-the inustrationoarig. 9,- an d entitled #anun its enclosed structure is usually mountedin an enginebase 38, where itinakesgearconnection with an engine driven shaft by means of apinion e. ation.. Two ports havebeen provideddnthel'fue1 pipe so as toppen therein n ear theedgepfthe throttle valvewhen closemand s'o', that-.one ofthepbrts {pore-.1.9 anale' ff buretorparthtfmrlii journal bearings forthe shaft; The throttle valvejli in its' relation with a iluid connection-.with the-,portsfofthe carof'a hold-down bracket 44, piloted about the stem of the distributor housing III, which bracket also has an arm 48 that operates to hold the assembly to the engine base 38 by means of a yield` abledevice 41 that also permits of relative angu' lar movement; The motive unit 48 comprises a suction chamber fashioned from a pair of cup e members 48 and 48,- in rixntorim engagementV 'and cooperatingito 'clamp the edge of a diaphragm 501111 sealing'relation thereto. A spring 82 isfeonfined within the cup 48 and engages the center of the diaphragm 80 to urge it toward tthe supporting arm 42, there being secured to the center' of the, diaphragm a link, 54, necked in at iii to .provide .stops'for shoulders 58 Vengageable withfthefarrn 42iatly each side of a hole 5lV in the farm 42 through'whichthe link pases. 'I'he link 5,4.hasa pivotalgconnection at 58 with an arm 88, which arm is clamped about the stem 45 of the timerv distributor in theY usual manner.

Movement L onth e diaphragxn, then, changa the maar reaniigof the'iprcket inland, arm as. therebyvshifting the time-.of circuit breaker oper- The carbretreoiiibris die indue- .tionpipe oranextension'thereof from `the engine,

and'may include theventuri 1,12 allasissubstan- ,tially described injthepatentto W.-N. Ewart 1,961,747.-1 In theillustratedembodiment the carburetor part 18 Vis ofthedownfdraft carburetor` type, in which Athe venturi is'situatedjon thecarvb uretorJ side of: ythey 'throttlevalvd while the if? .the throttle valve. ".'l'hef throttle4 valve here illustrated, isof theputterfly rtype and comprises a disc 16`mounted'oh ath'rottle shaft 1 8 b'y means f 'bones 'erfand "s4 or taeter;

. Y -eme im@ whtmavhe called a ,man pressure rts maybesuccessively transferred to oppofzoneV 8K8 .andffa, IQW'EpreSSm- *211mgv The boss ,uislet/substantiels@ end .makes provisio'njfor disclosure.,referenceis here thf am! flitesV formingy .the l ports v and passages specific vtothecntrol means. '1

for the throttle shafttnrugn the poss a4. At one .branchlOVthathasa uid connection with the' inotive unitn ineansrof a pipe or tubing |02, andthe coupling natures |704 and. l06. if 1 f Where the shaftjlextends across the passagey 88, it isfprovidedwith a pair Aofcrossfbores |08 and il 0 at. auch., an angle-f as-A to monde ready communication between the ends ofthe'p'assage .88 whilethe Ithrottle v:valve is-closed and opened to ,a substantialzpoint, Abut such-.that the. two ends of .the passage 88-cwillbe closed off from one another.whenthethrote .valve has vbeenymovei a xedlstopl I5. adapteg:ltol engage an extension I I6 `or Il] respectivelyA ofthe boss 84, for limiting the rangen; thrqmemovement. VAfter thepas- A.sairesandL drill holes have been formed.` the.

There ia'a'drill hole 9.8 ending inaport 9 2 nor- 1 mallgopening into thehigh pressure none'86 -just ,above thefedgeof the throttle' valveJ .when-it is CIQSed. there aisgpemg 'a'. erinnere .s44 ending m a port 8 6norinally` opening into .the lo'wpre'ssure zone 88 vof thefuel; pipe. There isthen-provideda .pasage 88 thatintersectathedrill holesf'and '94, as welles `Vintersecting] thefjournalbore 8| v K end of ,the passage .88, there is a communicating 4o a it will follow the indications of` the curve f -g- [11,131,418 starting ends of the same-may be closed ofi I inserting plugs as H8, |20 4and yI22. s1.ch that there is a fluid tight connection between the port-92 through the passages 90, 9 8; the inter ruptibl connection :|06 and *l l0; n and thence t0, the'motive unit lll by' means cache branch loo and p1pe|oz. -w

1 With structure so constituted. provision is then made for controlling `vthe ignition timing'jstrictly cally illustrated by the solid line curve` the pressures that usually'jobtain for "one type of engine, where the fuel .induction pipe hasthe l single port A92, the curve depicting the pressures `for all ranges of engine speedasjthefthrottle position to that position of wide open `or maximum speed operation. This curve comprises] the *resulting advance cur've is shown in Fig.`9,f`as

ff-a-hP-lo-l, which` provides tco much timing advance for the speeds above 40 mgp. There ',is also shown in Fig. 8 a dash line curve, comwith the pressure curve a-d-e, is: easilyl con. trollable to prcvide'the desiredamount andchar-y prising branches d and e representing the resultant pressure occurring atthe diaphragm" of l the expansion unit, or in the passages leading theretopwhen the supplemental port 96 is "added to the control mechanism, and is used inconjunctionv with the port 90 through'ftheinterruptibie mechanismof the shaftil.l 'I'heresultingadvance curve by addition of the supplemental portl is shown in Fig. 9 by the curvmf-g- The Yphysical structurejoperatlng in accordance acter of automaticspark timingshiftL so that h-i-j in Fig. 9.

In one type of automotiveengine, andwhich may be said to be that illustrated, the. initial vsetting of the spark timing relation is about 10 ahead' of dead center. With that initial setting,

""asfan example, itj is desired in that particular i engine to have no changein ignition timing during an idling range or `stage of speed,k which-stage 'may be characterized as extendingfrom a condition of rest to and `in'cludinga road speed of about'` l2 m.A p. h. or engine speed of 'about 650 'R. P. M. Similarly, for the same type f engine,

it is desired to effect a gradually increasing change in spark timing by centrifugal mechanism subadvance curve of Fig.A 9. Itis also -desirableto j during which there'will be afgradualengine opspeed during which ,the amount ofautomatic shift will be decreased,` and nallybe cut=ofi' be substantially the sameth'roughout.

'i-i;; Yalve -is opened from an erigineidlingQr closed man-. branches a-b-c, of which thev branches b andc aretoo greatin momen't of vforce to' accomplish lthe desired operation of thejmotiveunit. `The Y* -as applied tov n that one type fof engine, as

Approximate f speed rangen' Sissa munggl-. `o to iam. pfiilk'.

.laver Iload -and .engine Excessive.. Those. `speeds at l th to Y .exacting;conditions.A

portion ofthentirespeed rangepver whicha ,characteristic timing-alterationfis to be effected.

The. separate-speed vbands have beendesignated on the #2.Roadloadsparkadvance curve in Fig. 9

of-the drawings by means o fgbracletswith the `indicationsf;1st.2r1d. 3rd,i.4th. anafth-n .c .Wi th `specific referencetofthe graphs in Eig. 9p thefdesired spark timing shiftis repwxjesenteclbyv i)k .end oi rtlieent'e; speed "rangc,-where `progress is under theiurgeI offsorne excitement .on necessity 'j and the engine lis operati the .graph or curve'whose connected-branches arev indicated as f -a-hvt-iyg This graph indicates; an, absence oitimershift durmsthe .brmc'h fwornrst stage. an increasing timeifshift during y the branch :g or .secondstasera. maintained nxed amount of timer shift Y Yduring the branch, la .or g third stage, anda `decreasing' amount qttimer shift duringthe branch-i1 or theffourthistage.

:with an absence of any automatlc-timeL-Shlft overthe branchjorl ftl'istage.fv Referring to the upper reaches ofA thisl desired spark! timing curve, itywill b e noted that after .theentrance uponk thefourth stage, which is,;indi c8ted bythe l dashed line beginning atabout v 40u11. p.,h., .and

where thegmaximum Aamount lof spark timing shift has been accomplishedthattlie `timer set? ting throughout the remaining higher speeds of the engine range follows substantial 1y;a flathorizontal line, thereby-, maintainingglthe greatest' amount V of timer shift between 4about47'? and. 499

v aheadl of top .dead center "throughout-both y'they erated change in ignition timing, av cruising band or stage-of engine. speed duringwhich the auto-L: matic shift in timing will be maintained substantiallyconstant or equal in amountover the .cen- .trifugaladvance followed by a travel band of v sl'ieecls above about .4 0 m. p.' h. Erorn'this observa@ .tion ojthedesired sparktiming curve, i't/ wiliebe readily. apbaretthat tbe-entire. renee of speds, -might .bedlvlded into'.v four A stages instead. of ilve,`

as has been done above, and might'pe termedas -f f the idling rspeed lband wouldbe coextensive with.

f wouldcons'ttute another. nam'effo'r' thejcruising The accompanying table sets out the character- `isticsof the above indicated speed bands or stages band.v Inasmuch as thespark' timing c ifir'vefory the 4travel band yand excessive band substantially f engine has been arbitrarily' divided into five stages ingthroughoutl the engine speeds above 40 m. p.` h., these two bands can' be included in one and termed the running band, especially since acon- .siderable portion of automotive travel of the pres-- ent day appears to'be at speeds of 40 m. p. h. or f ,more-p `f Q When the automotive engine is set into operation and condition vfor idling, the condition of the control elements will be substantially as illustrated in Fig. 5 wherein the throttle `valve 16 is l substantially." closed 'or in thepositionillustrated high pressure zone 'follows the bore 99, and ilows into the 'passage -98, from` whence it moves through the cross bores |08 and H0 to the' opposite end 'of the passage 98, that is subjected to theV K l l l A A throttle, also rotates the. ycross bores I|08,andvr I il reduced pressure of the low pressure zone through the drill hole 94 and port 98. Due to the .ofw'theldiaphrag'm 5|) and its linkage with the relative Vsize of thedrill holes 90 and 94, thereysultingiluiddepression within the passages 98 and Inliisinsufilcient to result in any movement lmovablevpart :of the distributor. Consequently there is nomotivated shift in the spark timing during'idle speeds. This same conditionvof elements obtains until the-throttle valveV 16 is'opened slightly, or-tov that point whjerefthe edge ofl the throttle valve 16-is' substantially coincident' or opposite tolthe opening of 'theport 92, at which position` the port-be`gins to respond tothe pressures in the-low px'essure'zoneofthe induction pipe."That is 'to sa.y,`instead*ofatmospheric Y`pressureV entering into port 92, the porthas 'sumcient communication/with the' engine side ofvv the y "throttle valve to beaected'by the'low pressure the'partsof the control device have been 'cali-f therein; `and consequentlyithe `pressure at'the port '92, which is' a mixture of the two zones,.is

yless than atmospheric pressure; though flowing into the port 92 forflushinggthe passage 9,8; As

brated, this "change over' stage becomes* suiiimotive unit'fto collapsef'which marks the end of f the rst stage," and the beginning of the acceleration ban'd of speedV The 'portion of the spark timing 'curve thus fariollowed is indicatedin lAs the throttle valve 16 Isl-further' opened, the

' high pressure zonewithin the intake'or `fuel pipe has less effect upon the resultingpressure within the passage 9,8 and-branch-'l dueto thelfact that movement of the throttlev 16 inpassing-over the port 92 gradually cuts ci! the amount'of high pressurethat may enter 'the passage 98 by way of arm 59 o f 'the distributor isf actuated, and resulting inthat branch of the spark 4timingecurve v designated g. I

Tnisgreduated and increasing shirt is substantiallyy completed when the engine' attains a speed equivalent to about 20 m, p. h., at which point the link 54 engages the stopsprqvided bythe bracket, that preventany further shift in timing by any increase of depression'gwithin'the motive-unit.

Tnet eonditionobtai'ns' unal the engine produced 'suction falls so lo'w as to be unbalanced by the spring 52, which occurs for higher speedsatfabout ,40 m.. p. .,h. The spark A timing curve resulting from this phaseoflthe operation is illustrated at h. theillustrated embodiment it is desired to have a ilxed'amount of shift `for the third.A stage 'of about 17 over and above theadvance effected by the centrifugal kdevice which is illustrated by the #3 curve. 'continuing amount of shift extends" between about 20and 40 m. p. h. and ismaintained constant by `reason [ofthe linkage or the inotive unit' 'resting 'against y.the stops.

i Byfthetime the, throttle valve 164A has been moved toapositiontol attain road speedof about i0 m. p; h'.',the parts will berelated vto eachother v,

substantially as indicate'rdinpFig. 6.` The movementionne tnr'otuevaiyeto thet'posm'on has in etec't transferred 'the port 92 with vits drill hole of x the"i'nduction pipe.` lThis niovementofl'the with iesrecttol the passage 98so that 4they begin to operate as'an'interrupting means .between both ports 92 and 96 now. open into the lowgpressure zonefoflthe induction pipe and therebyfsubject all'ofr thejpassage 98 and the ,branch |00 Vwith its connectionto the motiveunit to low presstricti'ng communicationby way f the cross bores As thefthrottle valve'l is opened further to 'attain speeds above 40 m. p. h., the port 96 is ysofclc'Jse jtotlie 'edge of, the throttle valvey thatl it begins Vtobe aiected by the high pressure zone onthe' carburetor side'of'the throttle valve. yAs 'the throttle valve4 is opened more and more, the

high pressure Vzone has an increasing effectupon the supplemental port'soY that the port 96 actually acts as a bleed or relief vport to the passage 98.'

`99fto .thejopposite side of the throttle Avalve .16. so" that it' no w opens into-the low` pressureI zone.

`Avthe opposite endslof the passage 98.' fI'hough. p

"sure, ,the` relation'of th'e` port r96 with respect i to the edge of the throttle valve 16, and there- However, duringthis time while the portu92 -is being, transferred tothe low pressure zone which in turn subjects` the passage 98 to the depression within the induction pipe, thek interrupting means provide'd'by the throttle shaft becomes suiiiciently effective to reduce or cut ofi?y the in- .uence of the low 'pressure zone upon branch |09, until iinally aV lposition 'of throttle opening is reached as illustrated in Ilg.` 7, wherein the port 94 has been' transferred completely4 to the high pressure zone'- of the` induction pipe, and the. passage 98 isgentirely cut oil' from the influence' ofthe y"port" 92. Underthese conditions, the

depressionl or"1owipres'sure existent atvthe port 94, is insuilicient to maintain theymotive unit in 'its collapsed condition," and the timer again;

" assumes Yits retarded position as viewed in Fig. 5.

The'resulting 'sparkv timing curve effected by the i transition'during movement of the throttle from the position of Fig. 6 to Fig. 'l comprises the fourth .step or stage Aoi' spark timing control shown at i in Fig. 9. In other words, by 'thetime the throttle valve has been opened vto the equivaxlent of about. .m.'1p. h'. 'road`speed, vthe eiective operation o'fsthe motive unit is entirely cut oil?,

andlthe spark timing control from that point-on i `is wholly -in` response. to. the speed responsive` mechanismv lhereinbeiore Areferred to.

Above the speed of 60 m..p. h., that branch' of the curveeiIected by the speedresponsive mechanism is indicated ataand comprises that por-- tion of the sparking timing curve that begins to 2,131,413v atten out near theupper endofits speed range, andwhereadditional.advanceis apt to resultf 4i1;3-, damaging effects upgm-imeengine.-4 It will be observed that the sparkadvance.for-allspeeds those speedsfrom about .47 to ,about 49. It

. is to be recalled, too, that when; operation off the engine is on wide open throttle and with full load, that the spark timing may thence drop to vcondition obtains ,whether the ,-full load operation be at v{iO-mp. h. or at some speed between that and idle.

Whilethe embodiment of the present invenj tion as herein disclosed, constitutes a preferred. form, it is -to vbeunderstoodA that other. forms oming Withinv the scope of;

might be adopted. all c the claims kwhich follow.

What isfclaimed isas follows: 'r if 1. Ignition apparatus for internal ,combustion enginesI comprising inlcombination, a carburetor` having a throttle valve providingin the carburetor a high pressure zone anda'low'pressure zone, acircuit interrupteryanvengine drivenicam for operating the interrupter, a Vdevice'havingcommunication with the carburetor and responsive.` tothe combined pressure effect `in both zones fori controlling the 'angular relation betweenthe interrupter and cam in order to vary the ignition controlling the communication to prevent any timing .during throttle openings for an acceleration speed band, to maintain a predetermined -amount of` advance in timing duringthrottle openings for a cruising the amount of timing speed band, tol decrease any variation in timingdue. to the device Vduring tion enginehaving a fuelinduction pipe, a

throttle `valve in the-inductionpipe, and an igni-.f`

.tion timing device for .effecting the 'firing of the fuel charge, ofengineroperated suction con trol means for, changingthe time of fuel ignition comprising, ports and passages in the induction pipe andshaftof the throttle valve so-.located with respect tothe throttle valve when closed that there will be noY ignition during throttle openings vfor an idling.;

shift in timing of fuel speed range, thatthere ywill be gradually effected a predetermined amount of shift in timing during` throttle openings for increased engine Ispeed i operating conditionsextending over acceleration,

the cruising band.,V

and means including a partofthethrottle valve and passages in effecting the shift in timing whereby'little change in spark timing relation from apredeterminedangle will be effected forl throttle valve in theinductionpipe, and an ig-p; nition timing device for effecting the vfiring' of necting the 'chamber with said ymeans including ports in'v the induction pipe andmeans completing` fluid timing as the throttleis opened, vand means for,`v`

- pipe withy a throttle` valve the'induction'pipe vinto highfpressure and low pressure zones, fthe combination withl said -inductionl pipe of an expansion "chamber,` andiy means connecting the-chamber withv thefinductionpipe,r .said means 'includingfportsinthe-induction pipe f advance as: the throttle opens for speed increases so as to maintain a; fixed level o f spark advance over throttleiopen-y, ings for a travel speed band, and .to eliminate;

. duction pipe with. a

the time of fuel ignition comprising'- asuction valve solocatedwith respectt'o the throttlevalve operable unit connected'y with ports and passages i "in :the induction'pipe` and shaft 'Y of thejthrottle above about 40m. p. h. is substantially the same,

5, in thatan advance is maintained'throughout:y

when Aclosedthat one port will- 'open'intoa highpressure zone of the induction pipe, and' that a x second. port vwill open into a-'low pressure zone. ofthe induction pipe,' 'tl'1eports^= being" locatedl ,-near the edge `oflthevv throttle. valve4 whenclosed the speedc'ontrolledcurve, #3 of Fig. 9, which .so as to betransfer'redto oppositepressure-zones is as it should-be for those conditions, .That;

combining the effectof {both-4L ports-will vvbenonignition for r theextreme's of 'throttle openings.

.. i 14.- In a timer controlled qapparatus'whe'reinan internal combustion enginehas'a 'fuelfinduction apipe with' av throttle valve andl shaft dividing vthe induction pipe into high pressure and `lowpressure i zones, the combination gwith= isaid induction pipeo'f anexpansionv'chamber', and means con'- the inductiony pipe,

,successivelyzas thethrottlefvalvefis open`ed'fromva' substantially closedf position toa wide open 7 position, Wherebythef pressure resulting from 26- `opening into -each of* ysaidzones,,apassage di- 'rectly connecting -both 'the ports opening into each zone, and valve meansfin'` the passage, in-

cluding crossbores. through the: throttle' shaft,

for closing ofil thev communication of said ports.

In-a timer controlledapparatus wherein an internal combustion engine hasa. vfuel induction port opening into each zone', and-valve rmeans throttle openings for operation in an. excessive speed band.. f rz 2. The combination with ani internal combusv Viny the passage actuated by thelthrott1e""shaft connectionbetweenY the expansion chamber and one of ,said ports V.atvall times. v f

:lol

,35, andl shaft dividing openin'gf-into-each'of said fznesj. a passage iirr-A tercepted by the-thrOttIeshaft connectingfeach .1

zone portsjin :response to the;'throttle' positiox'n` kone of said portsbeingincommunicationfwith the expansion lchamber at allftimes; Y v6. .Ina timer` controlledlapparatus wherein an internal combustion engineV haspfaffuel ,induction pipe vwithfa throttle .val'vefandj shaft dividing ;the'induction y-pipe intov high pressure and 'low pressurerones, the .combination -EwithV said -induction pipe of i an expansion" chamber, and means connecting. thev chamber with 'the induction pipe,- said v'sol means-including vports in thein- `f duction pipe opening into each 'of said zones,- and Y one .of which is `always innominunication: with. x the expansion chamber, a passage' interconnect'- ing both portsopening into'each' zone,-and valve cruising, and travel speed bands, and that there j will be anentire-absence of shift in timing'during throttle openingsfor anexcessiye speed band-,.`

shaft for controlling the influence. of the ports means;v in the passage comprising cross :bores and. the expansionchamber.- f

an internal combustionv fenginehas a' fuelin- -dividing the inductiony pipe into said induction pipe zone,l one of ywhich "throttle 1 valve and shaft L high (pressure r and low pressurezones, the-"combination ywith of angexpansion" chamber, v l. and f, `means* connecting the' chamber with vrthe' induction pipe, said means" including ports" provided by the. induction Ipipe opening: .into-fetich ports is 1n vo'o'n's' liant communie;

sage when-the Ithrottle shaft: isx-rotated to subrstantially wide c openthrottle positionzv;

8.V An automatic-:timer controlling apparatus for-internal combustion engines; comprising in combination, means'iconnected tothe said timer -for oscillatingthe same, lsaid-:means including an expansion chamber providing amovable mem' ber, a fuel induction vpipetonlthe, engine havingz a throttle valve ,therein, passages and ports in Vthe wall ofthe. pipe,`controlled `by the throttle valve andhaving.,connections'to theexpansion Y chamber and locatedv so that' the chamber will respond, to the-fluid pressures onfboth -sides of the throttlevalve as it isfopened sorasto cause a'. gradual shiftg-in timing' of .ignition during low throttle` engine operation',A so that :thechamber will `maintain a definite shift in, timingrof ignition yduring a predeterminedintermediate throtf tleengine operation, and sozthat the chamber will be rendered entirely ineifective duringengine operation beyondthe band,y of intermediate throttle-engine operations-u Y 9. In an internal combustionmotor having a `fuel induction pipe anda throttle valve, in which pipe suction is created by the operation `of the f engine, anignitionv timer, a suction unit for shifting -the timer `for changing theutime yof ignition, and -m eans connecting the yinduction pipe withA the suctionunit, said unit being responsive to-- v ropening intothe lowpressure zone, and means *including-the movement 'of 'the throttle` and .the suction created in the inductionpipe on thel engine side of the'throttle Valvewith modificaeffecting an advanceof timing during partly open'A throttle engine operation, and'for' gradually canc elling `the effected advance of timing "during increasinglypopen throttle engine'operation, said'Y unit being effective to maintain; a-predetermined amount of timer shift (over the intermediateband tion effected 4by the suction .in-the induction pipe' on thecarburetor side of the' throttle valve, for

of throttle openings, t

10. In an internal combustion'engine Vhaving f a fuel. pipe andal throttlevalve mounted on `a rotary;shaft,nin which pipe suction isfcreatedr v bythe operation of the engine,y and wherein the throttle valvedivides the pipe into "a high pres?? suregzone and.a.low pressure zone,l the combination comprising, an ignition; timer, a "suction vunit for shifting the timer to `vary thetime of l fuel ignition,1andV means connecting the suction unit with the induction pipe for controlling the shift of timer, said means comprising,-:a'port in the induction pipe opening into the-highpresf surezone, a port fin the pipe Aopeningintothe' y.low pressure lfzone, a .passage connecting the i ports and communicating vwith the suction unit, ,L A.and valve means operable inresponse to rotation 65 of the throttle valve determining the effect of pressure at bothports'upon the passage, whereby i y the suction unit' effects no shift :of timer during anidlingthrottlemange .of opening, effects a pro-fv gressive shiftof timerover an: accelerating throt tle rangeof opening, maintains la predetermined' amount of timer shift over ai cruising throttle range of opening, effects a` reverse timer shift overa travel-throttle range oflropening, and berange of opening; 1

comes l non-operative over an excessive-*throttle 11.-'1'In iin-automatic timer ycontrol mechanism I'for internal combustionr engineswherein an engine driven-`V timer *has `speed responsive mea-ns ,fori alteringjtheltinie of' fuel ignition in.v accoi'k -ance'withr engine speed;i and-has a suction unit for eifectinga'shft in timing'superimposed upon ka'speed` controlled alteration and in responseto fluidlpres'sureswithin an engine fuel pipe divided into high and low pressure zones by athrottle valve .and 4shaftthe combination-with said vfuel `.pipe ofyports and passagesfthereinVhaving'interyruptible" communication,- with"l 'each ,other and V.with both pressure zones'andl connected with the suction unit,,-and means'including 'the'throttle valve and shaft determining the effective component of each zonepre's'sure Withinthe'passage,

whereby the suctionunit effects a gradual shift in timing during an vacceleration throttle open- Y ing band and during a -travel throttleopening bland, and maintainsadefnite amount of shift in timing during an intervening cruising throttle opening band.'A

l2. In an automatic' timer controlv mechanism forinternal combustionV engines wherein an engine driven timer has speed responsive means for altering .the time of fuel ignition in `'accordance ;withenginespeed; and-'has a suction unit for .effecting a shift in timing superimposed' upon a speed`controlledalterationand iny response to .fluid pressureswithinan engine fuel pipe divided linto high and low Vpressure zones by a throttle vvalve andA shaft, the combinationwith said fuel pipe of, apassage in-the' fuel pipe, one end of -which connectsrwith the suction unit, a` portl at -eachend of 't`he'passage`, one of which ports opens vintothehigh pressure zone when the throttle ,is-substantially lclosed and .the`othe`r port shaft,.in'which there is atransition of each port opening and'during; an excessivev throttle' opening, Ybut will effect a gradually increasing shift over an acceleration'throttle opening, a gradually decreasing shift over a'travel throttle open- 4ing, and maintain a5 fixedamount of shift over :a cruising throttle openn'g'int'ervenin'g theiaccelerationand travelthrottle'openings 13. Ignition apparatus-for internal combustion lenginesgcomprisingincombination; an ignition timer with-means for varying the'time'cf` fuel ignition in accordance Withspeed, fandsuction actuated means for superimposing van'automatic control of timing upon the variation by speed, said suction actuated means including an expan- `sion chamber, athrottled Ifuel pipe, and means connecting the l expansion? chamber to the fuel pipel ata pluralityof ports -for variously combining the pressuresatithe ports intheir'effect upon the chamber,` Lsaid-*connecting means comprising a yport opening linto the fuel 'pipe Inear they edge [of thethrottle and vinto thefhig'hp'ress'ure zone when the throttle is closed,a second port'opening into thefuel pipe near the edge of the throttle and into ,the low pressurefzone when the throttle is closed,-said lthrottle'when moved tov wide open position successively transferring the first mentioned port to th'elow pressure zone of the fuel'-pipe,-and thenc'e'transferring the second mentioned port to the'high pressure zone of the: fuel pip'e, 7vh'erebyy the resulting pressure in the connecting means is insufficient to actueffect a shift in timing, over vthe variation of' f the throttle valve is closed, but operable upon v2,131,413 l Y internalv combustion engine has a fuel `induction l' pipe With'a throttle valve `and shaft separating the induction pipej into high and vlow p ressure ate the expansion chamber during both extreme positions of throttleopening, but is operable to timing in response to speed, for allpositions of throttle opening between the said extremes ofk throttle opening.

14. In a timer controlledapparatus whereinv an internal combustion engine has a fuel induction pipe with a throttle valve and shaftseparating theA induction pipe into high and low pressure zones, and in which apparatus an expansion chamber` operates to alter the time of fuel ignition, the combination with said expansion chamber of means for selectively connecting the.l chamber with either or both zones of the induction pipe, and comprising a boss. on the indue tion pipe providing a passage Way transverse to the axis of the induction pipe, with ports at each end of the passage way opening into oppositev zones of the induction pipe and near the edge of the throttle valve when closed, and means provided by the throttle shaft for intercepting free flow through the passage way, said means oper-v ating upon opening movement of the throttle shaft from its closed position so as to gradually cut off communication through the passage bev tween the ports. f

15. The combination set Aforth in claim 14, wherein the intercepting means provided by the throttle shaft comprise angularlydisposed passages therethrough normallyproviding communication from end to end of the passage when throttle shaft rotation to entirely interrupt fluid passage therethrough at road speeds substantially above 60 m. p. h.

16. In a timer controlled apparatus wherein an zones, and in 'which apparatus an, expansion chamberoperats to alter the time of fuel igni tion, the combination withsaid expansionchamber of means ffor selectively' vconnecting the chamber with either or both-zones of the induction pipe, and comprising a boss on the inductionpipe.intersected'by'the throttle shaft, said boss being -drilled transverse to the axis of the nductionpipe to'provide a passageway,` and' a duct joining one end of the.v passage wayand having communication with the expansionA cham ber, said induction pipe havingports providing communication with vthe induction vpipe at each end of the passage Way,;one of thesaid ports being located at the juncture :ofthe duct and passageend and `vopening into the induction pipev near .the edge of the throttle valve and on the engine side thereof, another of said ports leading from the otherend of saidy passage way into the induction pipe 'near the edge of the throttle Avalve when closedand on the carburetor side..

thereof, said intersecting portionof the throttle shaft providing cross bores adapted to close off communication between opposite ends of the passage Way at a predeterminedthrottle valve position. Y 17.'The combination set forth V`in claim v1'6,

wherein the expansion chamber is subjectedto- I the pressure at both ports kduring all throttle .positions between' closedy and said predetermined throttle position, and isconnected with only one.

predetermined throttle position.

of said ports for all throttle positions above saidA alsl EvERETr H. l 

